﻿#region BSD 3-Clause License
/* Copyright (c) 2012, Intel Corporation
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *    
 * 3. Neither the name of Intel Corporation nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;

namespace OpenHopla.Geometry
{
    public class Chain
    {
        private List<OrderedPair> _points = new List<OrderedPair>();
        private List<LineSegment> _segments = new List<LineSegment>();
        private List<double> _segmentLengths = new List<double>();

        public Chain(IEnumerable<OrderedPair> points, bool closeChain=false)
        {
            #region Parameter Validation
            const string param1Name = "points";
            if (points == null)
            {
                throw new ArgumentNullException(param1Name);
            }
            #endregion

            AddPoints(points);
            if (closeChain) CloseChain();
        }

        private void AddPoints(IEnumerable<OrderedPair> points)
        {
            if (points != null)
            {
                foreach (OrderedPair point in points)
                {
                    AddPoint(point);
                }
            }
        }

        private void AddPoint(OrderedPair point)
        {
            #region Parameter Validation
            if (point == null)
            {
                const string paramName = "point";
                throw new ArgumentNullException(paramName);
            }
            #endregion

            if (Points.Count > 0) AddSegment(Points.Last(), point);
            _points.Add(point);
        }

        private void AddSegment(OrderedPair pointA, OrderedPair pointB)
        {
            #region Parameter Validation
            const string param1Name = "pointA";
            const string param2Name = "pointB";
            if (pointA == null)
            {
                throw new ArgumentNullException(param1Name);
            }
            if (pointB == null)
            {
                throw new ArgumentNullException(param2Name);
            }
            #endregion

            LineSegment segment = new LineSegment(pointA, pointB);
            _segments.Add(segment);
            _segmentLengths.Add(segment.Length);
        }

        private void CloseChain()
        {
            AddSegment(Points.Last(), Points.First());
        }

        public ReadOnlyCollection<OrderedPair> Points
        {
            get
            {
                return new ReadOnlyCollection<OrderedPair>(_points);
            }
        }

        public ReadOnlyCollection<LineSegment> Segments
        {
            get
            {
                return new ReadOnlyCollection<LineSegment>(_segments);
            }
        }

        public ReadOnlyCollection<double> SegmentLengths
        {
            get
            {
                return new ReadOnlyCollection<double>(_segmentLengths);
            }
        }
    }
}
